"Inhale it and see?" The collaboration between Thomas Beddoes and James Watt in pneumatic medicine

The collaboration of Thomas Beddoes and James Watt in the development of pneumatic medicine--the treatment of disease by the breathing of airs--is well known but little understood. Its protagonists presented the venture as an empirical one, in which the efficacy of different airs was tested independently of theoretical considerations. Historians have generally accepted that claim at face value. We contend, on the contrary, that the divergent theoretical chemical commitments of Watt and Beddoes significantly shaped their different approaches to, and their interpretations and expectations of, the pneumatic project. In particular, Beddoes's broad adherence to Lavoisian chemistry gave him an oxygen-centred approach to pneumatic medicine, while Watt's ongoing belief in phlogistic chemistry inclined him to expect great things of "hydrocarbonate." In addition, we show that a close examination of Watt's experiments and writings in his collaboration with Beddoes reveals a great deal about Watt's chemistry of airs.